Re: [PATCH] Nick's scheduler policy v7

[Nick Piggin]

Martin J. Bligh wrote:

> > I didn't miss 5 revisions, I'll just stick to using my internal
> > numbering for releases.
> >
> > This one has a few changes. Children now get a priority boost
> > on fork, and parents retain more priority after forking a child,
> > however exiting CPU hogs will now penalise parents a bit.
> >
> > Timeslice scaling was tweaked a bit. Oh and remember raising X's
> > priority should _help_ interactivity with this patch, and IMO is
> > not an unreasonable thing to be doing.
> >
> > Please test. I'm not getting enough feedback!
>
> Well, it's actually a bit faster than either mainline or your previous
> rev whilst running SDET:
>
> SDET 128  (see disclaimer)
>                           Throughput    Std. Dev
>              2.6.0-test4       100.0%         0.3%
>         2.6.0-test4-nick       102.9%         0.3%
>       2.6.0-test4-nick7a       105.1%         0.5%
>
> But kernbench is significantly slower. The increase in sys time has 
> dropped from last time, but user time is up.
>
> Kernbench: (make -j vmlinux, maximal tasks)
>                              Elapsed      System        User         CPU
>              2.6.0-test4       45.87      116.92      571.10     1499.00
>         2.6.0-test4-nick       49.37      131.31      611.15     1500.75
>       2.6.0-test4-nick7a       49.48      125.95      617.71     1502.00

Thanks Martin. OK, so the drop in kernbench is quite likely to be what
I thought - elevated priorities (caused by eg. make waiting for children)
causing timeslices to shrink. As long as its not a fundamental problem,
this should be able to be tweaked back.

Yeah, I guess the random kernel and user times are probably due to cache.



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